In this paper, the well-established probabilistic seismic hazard - Poisson occurrence model - technique is applied to estimate the seismic severity of Syrian region.Syrian seismic catalog, which extends from 19 AD to 2012, as well as seismotectonic features of the region have been utilized. The seismic hazard assessment carried out using eight seismic active zones based on tectonic settings and spatial distribution of the seismic activity. We assessed the modified Gutenberg-Richter Model parameters and the maximum credible earthquake magnitude for each seismic zone.Suitable numeric attenuation models have been used for the considered seismic zones. An increment of 0.1x 0.1 degree is used. The seismic hazard maps are developed for return periods (50, 100, 175, 475 and 975 years) and for the seven structural periods. Integrating PGA to PSA hazard maps have done based on site-effect factors of PSA/PGA. Seismic hazard curves are obtained for all major cities. Relatively high levels of PGA as well as PSA are found in regions: Lebanese part of DSFS, Al-Ghab region of Syria, along the border of Turkey and Bitilis zone. Remarkable seismicity has noticed in the eastern part of Syria.

Probabilistic seismic hazard analysis (PSHA) is a foundational element for determining design forces for new buildings and assessing the safety of existing structures. Consequently, decisions regarding the protection of urban infrastructures hinge on the outcomes of the PSHA. In recent years, numerous seismic hazard analyses have been conducted in Tehran, often yielding significantly divergent results. Such discrepancies can mislead analysts and stakeholders involved in urban safety. This article investigates the primary causes of variability in hazard results and quantitatively expresses the uncertainty associated with these findings. To achieve this, the Cornell-McGuire approach for PSHA is employed. The study's results indicate that the selection of ground motion prediction equations (GMPE or attenuation relationships), seismicity parameters(λ), and minimum magnitude(mmin) are critical factors contributing to this variability. Therefore, it is recommended that greater care be taken in selecting these parameters for PSHA conducted in Tehran.

The study area encompassed by the 49.5o–54oE longitudes and 34o-37oN latitudes. The aim is to develop a model for seismic hazard assessment is based on employing fuzzy sest theory. To carry out seismic hazard analysis in the framework of fuzzy sets theory, all of the variables converted into triangular fuzzy sets by using of MATLAB software. After applying different combination of them and extracting output in the framework of fuzzy, they became defuzzy by using surface center method. As a result, the hazard curve has been drawn for the site. PGA values for this region are estimated to be 0.35g and 0.12g for 475- and 50-years return periods, respectively.

A probabilistic seismic hazard assessment in terms of Arias intensity is presented for the city of Tehran. Tehran is the capital and the most populated city of Iran. From economical, political and social points of view, Tehran is the most significant city of Iran. Many destructive earthquakes happened in Iran in the last centuries. Historical references indicate that the old city of Rey and the present Tehran have been destroyed by catastrophic earthquakes at least 6 times. Existence of active faults like North of Tehran, Mosha and North and South of Rey is the main causes of seismicity of this city. Seismicity parameters on the basis of historical and instrumental earthquakes for a time period, from 4th century BC to the present time are calculated using Tavakoli’s approach and Kijko method. The earthquake catalogue with a radius of 200 km around Tehran has been used to calculate seismicity parameters. Iso-intensity contour lines maps of Tehran on the basis of different attenuation relationships are plotted. They display the probabilistic estimate of Arias intensity with Rock and Soil beds for the return periods of 72, 224, 475, 2475 years. SEISRISKIII software has been employed for seismic hazard assessment. Effects of different parameters such as seismicity parameters, length of fault rupture relationships, and attenuation relationships are considered using logic tree.

It is essential to use statistical models and theoretical analysis of the data for preparing comprehensive geological and seismic hazard mapping. A cellular automaton consists of an array of cells, each one of which has a finite number of possible states, together with a rule for updating all cells simultaneously based only on the states of neighboring cells. In the present paper, Ising cellular automation modeling has been used for establishing temporal relations between the energy releases of the seismic events that occurred in neighboring parts of the crust. The catalogue is divided into time intervals, and the region is divided into cells which are declared active or inactive by means of a threshold energy release criterion. Thus, a pattern of active and inactive cells which evolves over time is determined. The best model is chosen by maximizing the mutual information between the past and the future states. Finally, a Probabilistic Seismic Hazard Map is given for the different energy releases considered. The method has been applied to the wide range of Iran's geological and geophysical data and Iran catalogue from ISC and USGS from 1960 to 2009, (ISC and USGS).